This invention relates to a water propulsion unit for a water jet propulsion craft and more particularly to an improved arrangement for driving the water propulsion unit and for assembling the watercraft.
The use of water jets for propulsion units in a wide variety of watercraft is well known. One of the more popular types of such watercraft is a small, single rider unit that is designed to be operated by a rider wearing a swimming suit. With this type of unit, the engine should be mounted at a generally forward location so as to improve the balance of the unit and provides sufficient room for the rider. However, it is also desirable for the water jet to be placed at the rear of the watercraft and this means that its impeller is spaced a substantial distance from the driving engine. As a result, the drive shaft is very long and it is normally the practice to support the drive shaft by axially spaced bearings. This means that there are difficulties in radially aligning the bearings, drive shaft, engine output shaft and impeller. Unless properly aligned, the drive unit can cause undesirable vibrations. Furthermore, the arrangements for supporting the drive shaft which have been successful in avoid vibrations have made servicing of the individual components, such as removal of the water jet, difficult.
It is, therefore, a principal object of this invention to provide an improved arrangement for this type of watercraft.
It is a further object of this invention to provide an improved arrangement for supporting the drive shaft of a water jet type of watercraft wherein servicing is facilitated and alignment of the drive shaft, impeller and engine is simplified.
It is another object of this invention to provide an improved method for assembling a water jet type of watercraft.